The Visible Light Communication (VLC) technology refers to the technology of using the wavelength visible to human naked eyes to perform short-distance optical wireless communication in optical media within a scope of 400 nm to 700 nm. The VLC technology has advantages such as being immune to electromagnetic interference and the inexistence of interference related to a Radio Frequency (RF) system, and a spectrum range used in the VLC technology is an Unlicensed Spectrum. When the data transmission is performed with the visible light, at a sending end, the brightness of the visible light source can be modulated by speedily opening and closing a visible light source (e.g. a light emitting diode); and at a receiving end, after receiving a modulated optical signal, the optical signal is converted into data that can be processed by the receiving end.
When the communication is performed with the visible light, firstly it must guarantee that the normal use of the lighting equipment by the users is not affected while implementing the data transmission. It is required to consider the following two problems: one is to implement the high-speed data transmission; and the other is to support adjusting the brightness of the light source, namely Dimming.
In the Institute of Electrical and Electronic Engineers (IEEE) 802.15.7 visible light communication standard, there are roughly two ways for solving the brightness adjustment: one way is: in an idle/receiving state, the sending end implementing the dimming by using an idle mode, that is, by independently sending frames used for adjusting the brightness, and the transmission overhead is undoubtedly increased in this way; and the other way is: at the physical layer, performing the dimming by using an idle mode closely related to the modulation mode and channel coding scheme, only rough brightness adjustment can be performed in this way, and a brightness value is fixed, which reduces the flexibility of the dimming.